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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 GfhqZW+/E218LA3Y8CRzSKDKMJMlnCB0NQY7ShhtWSUtXGC89xJlqD/FpxglARn6
 G1RI65biAOiE2J/G0B+ieQ==

<SEC-DOCUMENT>0000052466-03-000091.txt : 20031121
<SEC-HEADER>0000052466-03-000091.hdr.sgml : 20031121
<ACCEPTANCE-DATETIME>20031121160852
ACCESSION NUMBER:		0000052466-03-000091
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031121
FILED AS OF DATE:		20031121

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IONICS INC
		CENTRAL INDEX KEY:			0000052466
		STANDARD INDUSTRIAL CLASSIFICATION:	SPECIAL INDUSTRY MACHINERY, NEC [3559]
		IRS NUMBER:				042068530
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		65 GROVE ST
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02172
		BUSINESS PHONE:		6179262500

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			REILLY WILLIAM K
		CENTRAL INDEX KEY:			0001127306

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07211
		FILM NUMBER:		031018315

	BUSINESS ADDRESS:	
		STREET 1:		345 CALIFORNIA ST
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104
		BUSINESS PHONE:		3027733854

	MAIL ADDRESS:	
		STREET 1:		345 CALIFORNIA ST
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wreilly_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<!-- - EDGAR Ease Plus 1.0                                   07/25/03  TT    -->
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
   <periodOfReport>2003-11-21</periodOfReport>
   <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000052466</issuerCik>
        <issuerName>IONICS INC</issuerName>
        <issuerTradingSymbol>ION</issuerTradingSymbol>
   </issuer>
   <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001127306</rptOwnerCik>
            <rptOwnerName>REILLY WILLIAM K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>345 CALIFORNIA ST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
         <isDirector>1</isDirector>
         <isOfficer>0</isOfficer>
         <isTenPercentOwner>0</isTenPercentOwner>
         <isOther>0</isOther>
      </reportingOwnerRelationship>
   </reportingOwner>
 <nonDerivativeTable>
   <nonDerivativeTransaction>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-11-21</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>A</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>245</value>
            <footnoteId id="F1"/>
         </transactionShares>
         <transactionPricePerShare>
           <value>30.66</value>
         </transactionPricePerShare>
         <transactionAcquiredDisposedCode>
           <value>A</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>2229</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
 </nonDerivativeTable>
   <footnotes>
      <footnote id="F1"> Represents shares acquired by reporting person as payment of retainer fee pursuant to Ionics, Incorporated 1998 Non-Employee Directors Fee Plan in a transaction exempt under Rule 16b-3.</footnote>
   </footnotes>
   <ownerSignature>
      <signatureName>/s/William K. Reilly</signatureName>
      <signatureDate>2003-11-21</signatureDate>
   </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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